Wave simulation device and method in geotechnical centrifuge

Abstract

The invention discloses a wave simulation device and method in a geotechnical centrifuge, the wave simulation device comprises a model box, a wave absorbing structure, a transmission rod and a permeable wave making plate, the model box is filled with test water; the model box is arranged on a foundation, and a building is arranged at the end part of one side in the model box; the permeable wave making plate is fixedly installed on the other side of the interior of the model box through guide columns, the four corners of the bottom of the permeable wave making plate are each provided with one guide column, and each guide column is vertically fixed to the inner wall of the model box so that horizontal movement of the permeable wave making plate can be limited through the guide columns; the top of the permeable wave making plate is connected with a transmission rod, the transmission rod is connected with a transmission device, and under the action of the transmission device, the permeable wave making plate is driven to periodically reciprocate up and down to generate waves; and the wave absorbing structure is fixedly mounted at the end part of the other side in the model box and is used for eliminating waves reflected back from the building.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering tests, and in particular to a wave simulation device and method in a geotechnical centrifuge. Background Art

[0002] Wave machines are widely used in laboratory model experiments to simulate natural waves. Accurately simulating natural waves is crucial for theoretical research on wave machines. Generally speaking, generating waves is relatively easy; eliminating unwanted wave reflections is often more challenging. Currently, most wave generators use the movement of flat plates and wedges to squeeze water. Because flat plates and wedges are typically smooth, laboratory wave generation can produce secondary reflections at the wave generator, a reflection that does not occur in nature. These reflected waves overlap with the waves generated by the wave generator. After a period of time, the reflected waves continuously reflect, propagate, and overlap between the model and the wave generator, eventually superimposing on the waves generated by the wave generator. The wave shape gradually changes, no longer resembling the intended one. Consequently, the test data obtained at this point cannot accurately reflect the effects of waves on buildings. To address this issue, researchers have proposed a method in which the wave generator simultaneously generates waves and absorbs reflected waves, a technique known as "active absorption." This type of wave generator uses feedback from hydrodynamics to drive the wave generator using a mathematical model through a control system, thereby eliminating reflected waves. Furthermore, active absorption technology can effectively avoid resonance phenomena in water tanks and pools, greatly shorten the still water time between experiments, and reduce the generation of pseudo-harmonics.

[0003] Active absorption technology is currently relatively mature in conventional wave flumes. However, existing solutions in geotechnical centrifuges often use wedges or flat plates to generate waves, which also presents the problem of secondary reflection. However, implementing active absorption technology is extremely difficult, fundamentally because it requires a precise measurement and control system. However, the waves generated in geotechnical centrifuges are very small, and existing measurement methods often produce large relative errors. Furthermore, the model chamber of a geotechnical centrifuge is limited in size, especially for beam-type centrifuges, which typically do not exceed one meter in length, width, and height. This confined space makes it difficult to accommodate a large amount of equipment. Due to the inability to effectively eliminate secondary reflections, relatively mature wave generation devices are mostly found in drum-type centrifuges, making it difficult to achieve ideal wave simulation in beam-type geotechnical centrifuges. Existing wave generation efforts in beam-type geotechnical centrifuges often incorporate wave-damping devices on the side opposite the wave-generating plate to prevent wave reflections and maintain a good wave shape within the model chamber. Summary of the Invention

[0004] The purpose of this application is to provide a wave simulation device and method in a geotechnical centrifuge to address the technical defects that the wave generating devices in the centrifuges in the prior art cannot avoid secondary reflection and can only be provided with a wave absorbing device on the other side opposite to the wave-making plate. However, when there is a non-permeable structure such as a dam or wall in the geotechnical centrifuge model box, the wave absorbing device is blocked and becomes ineffective, making it difficult to maintain the wave shape during the experiment.

[0005] The technical solutions adopted to achieve the purpose of this application are:

[0006] A wave simulation device in a geotechnical centrifuge comprises a model box, a wave-breaking structure, a transmission rod and a hollow wave-making plate, wherein the model box is filled with test water;

[0007] The model box is set on the foundation, and a building is set at the end of one side of the interior of the model box; the hollow wave-making plate is fixedly installed on the other side of the interior of the model box through a guide column, and a guide column is installed at the four corners of the bottom of the hollow wave-making plate, and each guide column is vertically fixed to the inner wall of the model box to limit the horizontal movement of the hollow wave-making plate through the guide column; the top of the hollow wave-making plate is connected to a transmission rod, and the transmission rod is connected to a transmission device. Under the action of the transmission device, the hollow wave-making plate is driven to generate periodic up and down reciprocating motion to generate waves;

[0008] The wave-breaking structure is fixedly mounted on the other end of the interior of the model box and is used to eliminate waves reflected from the building.

[0009] In the above technical solution, the building is a trapezoidal structure.

[0010] In the above technical solution, the hollow wave-making plate and the guide column are both made of high-strength and corrosion-resistant materials.

[0011] In the above technical solution, the wave-absorbing structure is a fence board or other porous energy-absorbing materials.

[0012] In the above technical solution, the hollow wave-making plate includes a loading rod, a horizontal wave-breaking device, transverse ribs and longitudinal ribs, and the transverse ribs and longitudinal ribs are cross-arranged on the top of the horizontal wave-breaking device; the loading rod is arranged in the middle position of the top of the transverse rib, and the top of the loading rod is connected to the bottom of the transmission rod, so that the transmission rod drives the hollow wave-making plate to produce periodic up and down reciprocating motion under the action of the transmission device.

[0013] In the above technical solution, a plurality of holes are provided on the transverse ribs to reduce reflection of waves generated at the transverse ribs.

[0014] In the above technical solution, the horizontal wave-breaking device includes N horizontal plates, side vertical plates and a central vertical plate. The N horizontal plates are arranged vertically at equal intervals. The side vertical plates and the central vertical plate are assembled on the N horizontal plates in a horizontally layered modular assembly manner to form a multi-bin square tube structure distributed in a matrix; wherein N≥2.

[0015] In the above technical solution, the side vertical plates are fixedly installed on both sides of the horizontal plate 13 by tension bolts, and the central vertical plate is fixedly installed in the middle position of the horizontal plate by tension bolts.

[0016] In the above technical solution, a wave height sensor is provided in the model box for monitoring the height of waves in the model box.

[0017] A method for simulating waves in a geotechnical centrifuge comprises the following steps:

[0018] Step 1: Determine the model wave height based on the wave height to be simulated and the model scale, and determine the length of the hollow wave-making plate in the wave propagation direction based on the model wave height;

[0019] Step 2: Determine the frequency of the up and down reciprocating motion of the permeable wave-making plate according to the wave period to be simulated and the model scale;

[0020] Step 3: Determine the height of each square tube of the horizontal wave-breaking device according to the model wave height to achieve a better wave-breaking effect.

[0021] Step 4: Make a model according to the size of the actual project and the model scale, and install a wave height sensor in the model box to monitor the wave height in the model box.

[0022] Step 5: activating the transmission device according to the set frequency of the up-and-down reciprocating motion of the permeable wave-making plate. The transmission device drives the transmission rod to drive, thereby driving the permeable wave-making plate to generate periodic up-and-down reciprocating motion, thereby squeezing the test water in the model box to generate waves.

[0023] Step 6: Repeat steps 1-5 and collect test data.

[0024] The beneficial effects of the present invention are as follows:

[0025] 1. The wave simulation device in the geotechnical centrifuge of the present invention adopts a permeable wave-making plate, which can form reflected waves on the surface of the building. The reflected waves can pass through the permeable wave-making plate and be broken in the wave-breaking structure, thereby achieving the effect of maintaining the waveform for a long time during the test.

[0026] 2. The lower structure of the hollow wave-making plate of the present invention is a horizontal wave-breaking structure, which can eliminate part of the waves reflected from the building.

[0027] 3. The wave simulation device in the geotechnical centrifuge of the present invention can effectively eliminate wave reflections (except for reflections at buildings) without the need for precise measurement and control systems and active absorption technology, which is consistent with the interaction scenario between waves and buildings in actual engineering projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is a schematic diagram of the front cross-section structure of the wave simulation device in the geotechnical centrifuge described in the present invention.

[0030] Figure 2 This is a schematic side sectional view of the wave simulation device in the geotechnical centrifuge described in the present invention.

[0031] Figure 3 This is a schematic diagram of the structure of the wave simulation device in the geotechnical centrifuge described in the present invention from a top view.

[0032] Figure 4 This is a schematic diagram of the side elevation structure of the hollow wave-making plate described in the present invention.

[0033] Figure 5 This is a schematic diagram of the front elevation structure of the hollow wave-making plate described in the present invention.

[0034] Figure 6 This is a schematic diagram of the top view of the hollow wave-making plate described in the present invention.

[0035] In the figure: 1- model box, 2- building, 3- foundation, 4- wave-breaking structure, 5- guide column, 6- transmission rod, 8- hollow wave-making plate, 9- loading rod, 10- transverse rib, 101- hole, 11- longitudinal rib, 12- side vertical plate, 13- horizontal plate, 14- central vertical plate. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention are further described below with reference to specific embodiments.

[0037] A wave simulation device in a geotechnical centrifuge, see Figure 1-3 , including a model box 1, a wave-breaking structure 4, a transmission rod 6 and a hollow wave-making plate 8. The model box 1 is filled with test water, wherein:

[0038] The model box 1 is set on the foundation 3, and a building 2 is set at the end of one side of the interior of the model box 1 (the building 2 is a trapezoidal structure); the hollow wave-making plate 8 is fixedly installed on the other side of the interior of the model box 1 through a guide column 5, and a guide column 5 is installed at the four corners of the bottom of the hollow wave-making plate 8. Each guide column 5 is vertically fixed on the inner wall of the model box 1, so as to limit the horizontal movement of the hollow wave-making plate 8 through the guide column 5, so that the hollow wave-making plate 8 only produces movement perpendicular to the water surface within a limited range; the top of the hollow wave-making plate 8 is connected to a transmission rod 6, and the transmission rod 6 is connected to the transmission device. Under the action of the transmission device, the hollow wave-making plate 8 is driven to produce periodic up and down reciprocating motion, thereby squeezing the test water in the model box 1 to generate waves (the hollow wave-making plate 8 is a hollow structure along the wave propagation direction); the wave-breaking structure 4 is fixedly installed at the end on the other side of the interior of the model box 1, and is used to eliminate waves reflected from the building. The hollow wave-making plate 8 and the guide column 5 are both made of high-strength and corrosion-resistant materials; the wave-absorbing structure 4 is a fence plate or other porous energy-dissipating materials.

[0039] See also Figure 4-6 The hollow wave-making plate 8 includes a loading rod 9, a horizontal wave-breaking device, a transverse rib 10 and a longitudinal rib 11. The transverse ribs 10 and the longitudinal ribs 11 are cross-arranged at the top of the horizontal wave-breaking device. The transverse ribs 10 are provided with a plurality of holes 101 to reduce the reflection of waves at the transverse ribs 10; the loading rod 9 is arranged in the middle position of the top of the transverse rib 10, and the top of the loading rod 9 is connected to the bottom of the transmission rod 6, so that the transmission rod 6 drives the hollow wave-making plate 8 to produce periodic up and down reciprocating motion under the action of the transmission device, and eliminates part of the waves reflected back from the building through the horizontal wave-breaking device.

[0040] The horizontal wave-breaking device includes N horizontal plates 13, side vertical plates 12, and a central vertical plate 14. The N horizontal plates 13 are arranged vertically at equal intervals. The side vertical plates 12 and the central vertical plate 14 are assembled on the N horizontal plates 13 in a horizontally layered modular assembly manner to form a multi-bin square tube structure distributed in a matrix (the height of the horizontal wave-breaking device and the height of each bin square tube can be adjusted according to the module to meet the wave-breaking needs of different wave heights). Wherein, N≥2; the side vertical plates 12 are fixedly installed on both sides of the horizontal plate 13 by tension bolts, and the central vertical plate 14 is fixedly installed in the middle position of the horizontal plate 13 by tension bolts; the width of the horizontal wave-breaking device (perpendicular to the wave propagation direction) is the same as the width of the model box 1.

[0041] Furthermore, a wave height sensor is provided in the model box 1 for monitoring the height of waves in the model box 1 .

[0042] A method for simulating waves in a geotechnical centrifuge comprises the following steps:

[0043] Step 1: determine the model wave height according to the wave height to be simulated and the model scale, and determine the length of the hollow wave-making plate 8 in the wave propagation direction according to the model wave height.

[0044] The higher the model wave height is, the longer the length of the hollow wave-making plate 8 in the wave propagation direction is.

[0045] Step 2: Determine the frequency of the up and down reciprocating motion of the hollow wave-making plate 8 according to the wave period to be simulated and the scale of the model.

[0046] Step 3: Determine the height of each square tube of the horizontal wave-breaking device according to the model wave height to achieve a better wave-breaking effect.

[0047] Step 4: Make a model according to the size of the actual project and the model scale, and install a wave height sensor in the model box 1 to monitor the wave height in the model box 1.

[0048] Step 5: Start the transmission device according to the set frequency of the up and down reciprocating motion of the hollow wave-making plate 8. Under the action of the transmission device, the transmission rod 6 is driven to drive, thereby driving the hollow wave-making plate 8 to produce periodic up and down reciprocating motion, thereby squeezing the test water in the model box 1 to generate waves.

[0049] Step 6: Repeat steps 1-5 and collect test data.

[0050] For ease of explanation, spatial relative terms such as "upper", "lower", "left", and "right" are used in the embodiments to illustrate the relationship between one element or feature shown in the figures and another element or feature. It should be understood that, in addition to the orientation shown in the figures, spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, the element described as being "under" other elements or features will be positioned "above" other elements or features. Therefore, the exemplary term "under" can include both upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here can be interpreted accordingly.

[0051] Moreover, relational terms such as “first” and “second” are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any actual relationship or order between these components.

[0052] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A wave simulation device in a geotechnical centrifuge, characterized in that: It includes a model box, a wave-breaking structure, a transmission rod and a hollow wave-making plate, wherein the model box is filled with test water; The model box is set on the foundation, and a building is set at the end of one side of the interior of the model box; the hollow wave-making plate is fixedly installed on the other side of the interior of the model box through a guide column, and a guide column is installed at the four corners of the bottom of the hollow wave-making plate, and each guide column is vertically fixed to the inner wall of the model box to limit the horizontal movement of the hollow wave-making plate through the guide column; the top of the hollow wave-making plate is connected to a transmission rod, and the transmission rod is connected to a transmission device. Under the action of the transmission device, the hollow wave-making plate is driven to generate periodic up and down reciprocating motion to generate waves; The wave-breaking structure is fixedly mounted on the other end of the interior of the model box and is used to eliminate waves reflected from the building.

2. The wave simulation device according to claim 1, characterized in that: The building is a trapezoidal structure.

3. The wave simulation device according to claim 1, characterized in that: The hollow wave-making plate and the guide column are both made of high-strength corrosion-resistant materials.

4. The wave simulation device according to claim 1, characterized in that: The wave-absorbing structure is a fence board or other porous energy-absorbing materials.

5. The wave simulation device according to claim 1, characterized in that: The hollow wave-making plate includes a loading rod, a horizontal wave-breaking device, transverse ribs and longitudinal ribs, and the transverse ribs and longitudinal ribs are cross-arranged on the top of the horizontal wave-breaking device; the loading rod is arranged in the middle position of the top of the transverse rib, and the top of the loading rod is connected to the bottom of the transmission rod, so that the transmission rod drives the hollow wave-making plate to produce periodic up and down reciprocating motion under the action of the transmission device.

6. The wave simulation device according to claim 1, characterized in that: The transverse ribs are provided with a plurality of holes to reduce reflection of waves generated at the transverse ribs.

7. The wave simulation device according to claim 1, characterized in that: The horizontal wave-breaking device includes N horizontal plates, side vertical plates and a central vertical plate. The N horizontal plates are arranged vertically at equal intervals. The side vertical plates and the central vertical plate are assembled on the N horizontal plates in a horizontally layered modular assembly manner to form a multi-bin square tube structure distributed in a matrix; wherein N≥2.

8. The wave simulation device according to claim 1, characterized in that: The side vertical plates are fixedly mounted on both sides of the horizontal plate 13 by means of tension bolts, and the central vertical plate is fixedly mounted in the middle of the horizontal plate by means of tension bolts.

9. The wave simulation device according to claim 1, characterized in that: A wave height sensor is provided in the model box for monitoring the height of waves in the model box.

10. A wave simulation method based on the wave simulation device according to claim 1, characterized in that: The following steps are involved: Step 1: Determine the model wave height based on the wave height to be simulated and the model scale, and determine the length of the hollow wave-making plate in the wave propagation direction based on the model wave height; Step 2: Determine the frequency of the up and down reciprocating motion of the permeable wave-making plate according to the wave period to be simulated and the model scale; Step 3: Determine the height of each square tube of the horizontal wave-breaking device according to the model wave height to achieve a better wave-breaking effect. Step 4: Make a model according to the size of the actual project and the model scale, and install a wave height sensor in the model box to monitor the wave height in the model box. Step 5: activating the transmission device according to the set frequency of the up-and-down reciprocating motion of the permeable wave-making plate. The transmission device drives the transmission rod to drive, thereby driving the permeable wave-making plate to generate periodic up-and-down reciprocating motion, thereby squeezing the test water in the model box to generate waves. Step 6: Repeat steps 1-5 and collect test data.

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